HALO Style revamp - delete Drawables

- speech bubbles are centered
- number batches are roundand simplified, same color as in g+
- markers appear as dots above the bubble
- hiding and dimissing triggers text hints
- couple of bugfixes

WARNING: some of the drawables are good for xhdpi only for now and must
be scaled down for the other resolutions

Change-Id: I9a490c77ff1a438cd9b45e89ac2a5791775b2338